Patchwork ACPI / PCI: Do not try to acquire _OSC control if that is hopeless

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Submitter Rafael J. Wysocki
Date July 30, 2012, 8:40 p.m.
Message ID <201207302240.32480.rjw@sisk.pl>
Download mbox | patch
Permalink /patch/174087/
State Not Applicable
Headers show

Comments

Rafael J. Wysocki - July 30, 2012, 8:40 p.m.
If acpi_pci_osc_support() fails for the given flags, it doesn't make
sense to call acpi_pci_osc_control_set() down the road for the same
flags, because it will certainly fail too.  Moreover, problem
diagnostics is then harder, because it is not too easy to identify
the reason of the _OSC failure in those cases.

For this reason, check the status returned by acpi_pci_osc_support()
for PCIe support flags and do not attempt to execute
acpi_pci_osc_control_set() for those flags and print a message if
it's "failure".  For compatibility with the existing code, disable
ASPM in that case too.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
---
 drivers/acpi/pci_root.c |   11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

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Len Brown - July 31, 2012, 1:15 a.m.
Applied.

thanks,
-Len Brown, Intel Open Source Technology Center

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Patch

Index: linux/drivers/acpi/pci_root.c
===================================================================
--- linux.orig/drivers/acpi/pci_root.c
+++ linux/drivers/acpi/pci_root.c
@@ -573,8 +573,15 @@  static int __devinit acpi_pci_root_add(s
 			OSC_CLOCK_PWR_CAPABILITY_SUPPORT;
 	if (pci_msi_enabled())
 		flags |= OSC_MSI_SUPPORT;
-	if (flags != base_flags)
-		acpi_pci_osc_support(root, flags);
+	if (flags != base_flags) {
+		status = acpi_pci_osc_support(root, flags);
+		if (ACPI_FAILURE(status)) {
+			dev_info(root->bus->bridge, "ACPI _OSC support "
+				"notification failed, disabling PCIe ASPM\n");
+			pcie_no_aspm();
+			flags = base_flags;
+		}
+	}
 
 	if (!pcie_ports_disabled
 	    && (flags & ACPI_PCIE_REQ_SUPPORT) == ACPI_PCIE_REQ_SUPPORT) {